Squared shadows after rendering
Thanks all, problem solved. Squared shadows was solved according message user2859 in the spot settings, which erased the highest squares.


There was some other little squares after that, although image was usable after this setting. According user2859's next message I changed antialiasing settings in the rendering settings.


After theese steps was issue solved. All scopes settings(Waveform O, Vectorscope opacity, and Scope samples(the top left button on the window during rendering)) was on maximum during the tries.